walker etal



Sept. 10, 1963 E. J. WALKER ETAL 3,103,565

ELECTROMAGNETIC CIRCUIT BREAKER Filed Sept. 20, 1960 5 Sheets-Sheet 1 P1963 E. J. WALKER ET AL 3,103,565

ELECTROMAGNETIC CIRCUIT BREAKER Filed Sept. 20, 1960 3 Sheets-Sheet 2ll"? llllll WITNESSES= E J w ILNVIiINTkOIYRS ugene 0 er, :c orgm 6g aand William J. Pendy,Jr.

ATTORNEY Se t. 10, 1963 E. J. WALKER ET AL ,1

ELECTROMAGNETIC CIRCUIT BREAKER Filed Sept. 20, 1960 3 Sheets-Sheet 3Fig.6.

United hiatus Patented Sept. 10, 1963 This invention relates to circuitbreakers and more particularly to mechanisms for eflectin automaticopening of circuit breakers.

Circuit breaker engineering specialists are constantly attempting toprovide compactly constructed breakers having increased current carryingand interrupting ratings. These compact breakers are not only lessexpensive to manufacture; but they'also save space in control centers.Thus, panelboard and control panel builders can manufacture considerablysmaller and less expensive control centers; The industrial market is,therefore, pro ,vided with a less expensive installation that takes upless 1 plant space without a sacrifice in power rating or eiiiciency.

Accordingly, anobject of this invention is to provide an improvedcompactly constructed circuit breaker.

Another object of the invention is to provide a circuit breaker with animproved mechanism [for effecting automatic opening of the breaker.

A turther object of the invention is to provide a circuit breaker withan improved tripping mechanism that embodies a novel compactlyconstnucted tripping and latching structure.

Other objects of the invention will be explained fully hereinafter orwill be apparent to those skilled in the art.

According to one embodiment of the invention, a circuit breaker isprovided having three pole units disposed side-by-side within aninsulating housing. Two spaced supporting plates are disposed in thecenter pole unit serving to support an operating mechanism forcontrolling all of the pole units. The operating mechanism includes alatch member that engages and latches a memher that is releasable toeffect opening of the contacts in all of the pole units of the breakenThe latch member is, in turn, latched by a latching structure thatincludes a cylindrical metallic trip bar that is rotatably supported bythe supporting plates and is common to allof the pole units. The latchmember, which is latched by engagement thereofwith the periphery of thetrip bar, falls into a notch in the trip bar when the trip bar isrotated. This movement releases the releasable member. There is a tripmember in each of the three pole units supported on the common trip bar.An electromagnetic trip device is also provided in each ot the threepole units. Upon the occurrence of overload current conditions above apredetermined value in any of the pole units, an armature of theelectromagnetic trip device in that pole unit moves to engage the tripmember in that pole vunit to thereby rotate the common trip bar torelease the releasable member and effect an opening operation. The tripmemher in the center pole unit is adjustable to vary the amount of latchengagement between the trip bar and the latch member. The trip members[for the two outer pole units are of insulating material to insulate themetallic trip bar. These outer trip members also engage the outer sidesof the spaced supporting plates functioning as thrust bearings toprevent axial movement of the trip bar.

For a better understanding of the nature and objects of the invention,reference may be had to the following detailed description, taken inconjunction with the accompanying drawings in which:

FIGURE 1 is a top plan view on a reduced scale of a for each pole unitof the breaker.

2 circuit breaker embodying the principal features of the invention, apart of the cover being broken away to more clearly show some of theparts;

FIGURE 2 is a vertical sectional view of the circuit breaker takensubstantially on line 11-11 of FIG. 1, and looking in the directionindicated by the arrows, the circuit breaker being shown in the opencircuit position;

FIGS. 3A and 3B are plan views of the two spaced mechanism-supp ortin'gplates;

FIG. 4 is an elevational view of the supporting plate shown in FIG. 3B;

FIG. 5 is an elevational View of the trip bar;

FIG. 6 is a top plan view of one of the insulating trip members *for oneof the outer pole units;

FIG. 7 is a view taken substantially along the line VII-VII of N6. 6;

FIG. 8 is an elcvational view of the trip member lor the center poleunit;

FIG. 9 is a top plan view of the trip member shown in FIG. 8;

FIG. 10 is a side view of the trip member of FIG. 8; and,

FIG. ll is an elevational view of part of the tripping mechanism of theinvention.

Referring to FIGS. 1 and 2 of the drawings, the circuit breaker showntherein is of a three-pole type and comprises a base 11 (FIG. 2) and acover 13 both of molded insulation material. Cooperating barriers 14(FIG. 1) in the base and cover serve to insulate the three pole unitsfrom each other. A stationary contact 15, a movable contact 1'7 and anarc-extinguishing unit 18 are provided The circuit breaker alsocomp-rises an operating mechanism 19, and a latching device 2% disposedin the center pole unit. An electromagnetic strip actuating device 21 isprovided in each of the pole units for effecting automatic opening ofthe v A somewhat similar operating mechanism and breaker. latchingdevice is shown in the patent to Walker et al. Patent No. 2,892,054,assigned to the assignee of the instant application.

The stationary contact 15 for each pole unit is rigidly mounted on theinner end of a conducting strip 2-3, to the outer end 24 of which isattached to a sol'clerless terlninal connector 25 of atype well known inthe art. The mowable contact 17 for each of the pole units is mounted ona contact arm 27 that is pivotally mounted by means of a pin 29 on aswitch arm 3d. The switch arms 30 for the several pole units of thebreaker are all secured to an insulating tie bar 31 that is rotatablysupported in brackets 32 (FIG. 1) that are supported in the side wallsof the circuit breaker housing. Torsion spring members (not shown) biasthe contact arms 27 clockwise about their pins 29 to provide contactpressure in the closed circuit position of the switch arms 30.

The operating mechanism 19 is disposed in the center pole unit and issupported by means of two supporting plates 34 and 35 (FIGS. 3a, 3b and4) that are connected by means of a pin (not shown) that extends throughopenings 36 in the plates. Each of the supporting plates 34 and 35 hastwo leg portions 37 that extend into openings in the base 11 of theinsulating housing to receive securing members (not shown) that arefastened over 'member 57 by means of a pivot pin 63, and the toggle link55 is pivotally connected to the switch arm 3-0 for the center pole unitby means of a pivot pin 65. OvercenJter springs 67 are connected undertension between the knee pivot pin 61 of the toggle 53, 55, and a yokeportion 68 of the operating lever 4 1.

The contacts are manually opened by movement of the handle 49, in acounterclockwise direction, from the on to the on position (FIG. 2).This movement carries the line of action of the overcenter spring 67 tothe left of the pivot pin 63 causing collapse of the toggle 53, 55 andcounterclockwisemovement of the'tie bar 3 1 to open the contacts tor allof the pole units of the breaker. The latching mechanism 20 latches thereleasable member 57 in a manner to be hereinafter specificallydescribed.

As best seen in FIG. 1, the switch arm 311, for each of the pole units,comprises a pair of spaced members. The contact arm 27 is disposedbetween the spaced members of the switch arm 30. The toggle link 55comprises a pair of spaced links, only one being shown in FIG. 2,disposed on opposite sides of the switch arm 30 for the center poleunit. The pivot pin 65 extends through the double toggle link 55, thedouble switch arm 36 and through an elongated slot (not shown) in theinner end of the contact arm 27 for the center pole unit, which slotpenmits movement of the contact arm 27 relative to the 1Z5 engages theupper end of an adjusting pin 127' that switch arm 30, so that thetorsion spring (not shown) T can bias the contact arm 27 downward toprovide contact pressure. The above-mentioned slot also permits a wipingaction between the contacts during the opening and closing operations. I

The contacts are manually closed by reversemovement of the operatinghandle 49 from the off to the on position, which movement moves the lineof action of the overcenter springs 6'7 to the right of the pivot 63,whereupon the springs operate to straighten the toggle 53, 55 and closethe contacts with a snap action.

There is an electromagnetic trip device 21 in each pole unit or thebreaker. Only the trip device 21 in the center pole unit will bespecifically described, it being understood that the description appliesto the trip device 21 of all of the poleunits. The trip device 21comprises a fixed angular magnet yoke 75 having a fixed core 77 rigidlysecured thereto about which is wound an energizi-ng coil 79. Twoprojections 80 on each of the two opposite sides of the yoke 75, engagein openings in two side plates 81, only one of which is seen in FIG. 2,to support the yoke 75 on the side plates 81. The side plates 81 arerigidly secured to the insulating base 11 in a suitable manner. Theupper end of the fixed core 77 forms a pole piece 83. The lower end ofthe coil 79 is connected to a terminal 8-3 by a screw member 85.Flexible conductors 87 are connected, at one end, to the terminal '83and, at the other end, to the tail portion of the movable contact member27. The upper end of the coil 79 is rigidly secured to the inner end'ofa conductor 91, at the other end of which is mounted a terminalconnector 93. An armature, indicated generally at 95, is pivotallysupported by means of projections 97 extending from is supported by across member 121 that is supported by is slidably supported within asleeve member 129. The sleeve member 129 is supported by a plate 131that is supported between the trip device side plates 81. lower end ofthe pin 1Z7 engages a member 133 that is welded or otherwise attached tothe armature 95. The under surface 126 of the cam 125 is shaped so that,upon rotation of the cam, the pin 127 is moved up or down v depending onthe direction of rotation. This movement of the pin 127, through themember 133 attached to the armature 95, moves the armature about itspivot 97 varying the position of the armature relative to the magnetpole piece 83.

The top of the knob is provided with a pointer 137 (FIG. 1) and thecover 13 is provided with index points, thereby providing a visualindication of the adjusted position of the armature member 95.Adjustment of the armature is effected by inserting a screwdriver in aslot 139, and rotating the screwdriver to bring the pointer the sideplates 34- and 35. The latch member 141 is" biased by means of a torsionspring 145 (FIG. 11) in a clockwise or unlatching direction. The latchmember 141 has a latching portion 147 that engages and releasablyrestrains a latch tip 149 of the releasable member 57 to hold the tripreleasable member in the latched position. The latch tip 149 is turnedin and faces generally in the direction toward the pivot 59 (FIG. 2)about which the releasable member 57 moves during a tripping operation.The latch member 141 is of the slip otf type and is releasably held inlatching position by engagement of a shoulder portion 151 thereof withthe periphery of 1a cylindrical trip bar 153 that is part of a tripstructure indicated generally at 154. As will be hereinafter described,the trip structure 154 is common to all of the pole units of thebreaker. The trip bar 153 has a notch 155 (FIGS. 5 and 11) therein, thepurpose of which will be hereinafter explained. The trip bar 153 extendsthrough openings 156 (FIG. 4) in the supporting plates 34 and 35, whichplates rotatably support the trip structure 154 in the breaker. The tripbar 153 .alsoextends through suitable openings in the barriers 14 (FIG.1), and additional barrier members 156 cooperate with the trip bar 153to close those openings.

The trip bar 153 (FIG. 5) has a 157 intermediate its ends,;and knurledportions 158 at each of its opposite ends. A trip member 159 (FIGS. 2and 8-1 1) is brazed or otherwise attached to the knurled portion 157 ofthe trip bar 153. The trip member 159 has an extension 160 (FIGS. 8-11)having an opening 161 therein through which an adjusting screw 163(FIGS. 1 and 11) is threaded. The trip member 159 and the trip bar 153to which it is attached, are biased in a counterclockwise or latchingdirection by means of a torsion spring 165 (FIG. 11).

In addition to the trip bar 153 and the trip member 159, the tripstructure 154- includes two trip members 167 (FIGS. 6 and 7) or aninsulating material such, for

158 at the opposite ends of the trip bar 153. The trip members 167 arepress fitted to the trip bar 153. Each The knurled jportion' I theopenings 145 thereby functioning as thrust bearings to prevent axialmovement of the rod 153. For this reason, the insulating materialforming the tripmembers 167 comprises a material such, for example, aspolyamide (nylon) that can slide against the surfaces of the metallicsupporting plates 34- and 35 without much friction.

position, a circuit extends, through each pole unit, from the terminalstrip 91, through the coil 79, terminal 83, flexible shuntsS'i, movablecontact arm 27, movable contact 17, stationary contact 15, to theconducting strip 23. When an overload current above a predeterminedvalue occurs in, forexample, the center pole unit (P16. 2)

of the breaker, the armature 95 is attracted to the pole piece 83 and itrotates counterclockwise about its pivot 97. During this movement, thetail portion 170 of the member 133 that is attached to the armature 95,engages a part 173 of the trip member 159, rotating the trip member 159,and the trip bar 153 to which the trip member is secured, in a clockwisedirection against the bias of the torsion spring 165 (FIG. 11). Thelatch tip 149 of the releasable member 57, and the latch portion 147 ofthe latch member 141 are to the left of the pivot 143 of the latchmember'141; hence, the latch memberv 141 is biased in unlat-chingdirection by a component of the force exerted by the overcenter' springs67 as well as by the torsion spring 145. When the trip not-ch 155 in thetrip bar'-153. This clockwise movement of the latch member 141 about itspivot 143, releases the member 57. When released, the member 57 rotatesclockwise about its'pivot53 (FIG. 2) under the influence of the overcen'ter springs 67, causing collapse of they toggle 53, 55, and openingmovement of the switch arms 30' for all of the pole units. During thismovement, the handle49 is moved, in a manner well known in the art, to atripped position intermediate the cit and on positions, thereby giving avisual indication that a tripping operation has occurred. v

Before the contacts can be closed following an automatic openingoperation, it is necessary to reset and relatch the mechanism. This isaccomplished by moving the handle 19 counterclockwise fromthe-intermediate tripped position to the extreme off position. Duringthis movement, a projection 175 on the operating lever 41' engages ashoulder 1 77 on the releasable member 57 moving the releasable member57 counterclockwise about its pivot 59. Near the end of this movement,the lower rounded portion of the latch point 149 of the releasablemember 57, engages an outwardly extending arm 179 of the latch member141 and moves this memher to the latching position. As soonas theprojection 151, of the latch member 141 clearsthe corner of the notch154 of the trip bar 153,,the torsion spring 165- restores the arm 159andtrip bar 153 to the latched position. The latch portion 147 is thenin position engaging the latch portion 149 of the releasable member 57so that the contacts can be closed in the previously described "mannerby movement of the handle 49 to a that pole unit is actuated in the samemanner previously described, whereupon the tail portion 170 of themember 15 When the circuit breaker 9 is in the closed circuit 133 whichis attached to the armature 95, engages the arm 169 (FIG. 1) in thatpole unit rotating the trip member 167 and the trip bar 153 to which itis attached in a clockwise direction to effect release of the latch 141and releasable member 57 in the same manner hereinbefore described tothereby effect an opening operation of the circuit breaker. i

The compactly constructed trip structure 154 which includes the trip bar153, and the trip members 159 and 16 7, serves to latch the mechanism211. This trip structure 154, which is common to all of the pole units,is also disposed to be actuated by means of. the electromagnetic tripactuating device '21 in any of the pole units to effect automaticopening of the breaker. It is to be noted that the members 167 serve notonly as trip members; but they insulate the ends of the metallic tripbar 153, and they also serve as thrust bearings preventing axialmovement of the trip bar.

The amount of latch engagement between the projection 151 of the latchmember 141 and the periphery of the trip bar 153, can be varied byrotation of the adjusting screw 163 which is biased against thestationary cross plate 1119 by means of the torsion spring 165. Thisrotation moves the trip member 159, and the trip bar 153 to which thetrip member is attached, in either a I clockwise or counterclockwisedirection depending on the direction of rotation of the screw 163.Adjustment of the amount of latch 'engagementbetween the trip mem- 7 bar153, therefore, rotates in a clockwise direction, the i projection 151of the latch member 141 snaps into the her 141 and the trip bar 153 isimportant because, ifl there is not enough latch engagement, the breakerwill trip open accidentally under shock conditions.

v The above described invention provides an improved compactlyconstructed circuit breaker having a novel latching andtrippingmechanism for effecting automatic opening of the breaker.

While theinvention has been disclosed in accordance with the provisionsof the Patent Statutes, it .is to be understood that various changes inthe structural details and arrangement of parts thereof may be madewithout departing. from some of the essential features of the invention.

We claim as our invention:

1. A circuit breaker having relatively movable contacts and meansreleasable to effect opening of said contacts, a latch mechanismcomprising a latch member engaging and releasably restraining thereleasable means, a trip structure separate from the latch member andlatching the latch member in latching position, electromagnetic tripmeans comprising a magnetic member, an armature struc ture operable uponsufficient energization of the electromagnetic trip means to engage andmove the trip struc hire to eifectrelease ofi the latchmember, and meansfor tacts, a latch mechanism comprising a latch member engaging andreleasably restraining the releasable means,

. a trip structure comprising a generally cylindrical trip bar havingits periphery engaging and releasably restraining the latch member, atrip member connected to the trip bar, electromagnetic trip meanscomprising a magnetic member, an armature device operable uponsuflicient energization of the electromagnetic trip means to engage thetrip member to eliectvmovement of the trip bar to release the latchmember, and means for varying the position of the trip member toitherebyvary the position of the trip bar to adjust the amount of latchengagement between the trip bar and the trip member.

3. A multi-pole circuit breaker having relatively movable contacts ineach pole unit, an operating mechanism releasable to effect automaticopening of the contacts in r all of said pole. units, a latch mechanismcomprising a latch member releasable to release the operating mechanism,a trip structure common to all of the pole units comprising a generallycylindrical trip bar having its pee the trip member for that pole unitto move the common trip structure to effect releaseof the latch member,and means-for adjusting the amount of latch engagement betweenthecomm'orrtrip bar and the latch member.

4. A circuit breaker comprising, in combination, an

insulating housing, three pole units disposed side-by-side within thehousing, each of the pole units comprising relatively movable contacts,two spaced supporting plates,

an operating mechanism supported by the supporting plates and releasableto effect opening of the contacts in all of the pole units, a metallictrip bar extending through the supporting plates, the trip bar beingrotatable to effect release of the operating mechanism, a trip membersupported on the trip bar and associated with the center pole unit, aninsulating trip member disposed on each of the opposite ends of the tripbar, each of said insulating trip members being associated with adifferent one of the two outer pole units, theinsulating trip membersengaging the supporting plates to prevent axial movement of the tripbar, and means in each of the three pole units operable upon theoccurrence of an overload current above a predetermined value in theassociated pole unit toactuate'the trip member associated with theoverloaded pole unit to rotate the trip bar to effect release of theoperating mechanism. I

5. A circuit breaker comprising an insulating housing, three pole unitsdisposed side-by-side Within the housing, relatively movable contacts ineach of the pole units, two spaced supporting plates, an operatingmechanism rebar, means in each of the three pole units operable upon theoccurrence of certain abnormal current conditions in" the associatedpole unit to engage the trip member for that pole unit to rotate thetrip bar to effect release of the operating mechanism, and means foradjusting the amount of latch engagement between the trip bar and? thelatch member.

7. A circuit breaker comprising an insulating housing, three pole unitsdisposed side-by-side within the housing, relatively movable contacts ineach of the pole units, .tWo spaced supporting plates disposed in thecenter pole unit, an operating mechanism in the center pole unitreleasable to eifect opening of the contacts in all of the pole units,

' a latch mechanism in the center pole unit comprising a lat-ch memberreleasable to release the operating mechanism, a trip structurecomprising a cylindrical trip bar separate from the latch mechanism andhaving its periphery engaging and releasably restraining the latchmember, the trip bar being rotatably supported by the supporting plates,a trip member supported on the trip bar and disposed within the centerpole unit, an insulating trip member disposed on each of the outer endsof the trip bar, each of the insnlating trip members being associatedwith a different one leasable to effect opening of the contacts in allof thepole.

units, a latch mechanism comprising a latch member latching theoperating mechanism and operable to release I the operating mechanism, atrip structure comprising a cylindrical trip bar having its periphery.engaging and releasably restraining the latch member, the trip bar beingrotatably s'up-ported by the supporting plates, a trip member supportedon the trip bar and disposed Within the center pole unit, an insulatingtrip member disposed on each of the outer ends of the trip bar, each ofthe insulating trip members being associated with a different one of thetwo outer pole units, the insulating trip members enthree pole unitsdisposed side-by-side within the housing, relatively movable contacts ineach of the pole units, two

spaced supporting plates disposed in the center pole unit, an operatingmechanism in the center pole unit releasable to eifect opening of thecontacts in all of the pole units, a latch mechanism in the center poleunit comprising a latch member operable to release the operatingmechanism, a trip structure comprising a cylindrical trip bar separatefrom the latch member and having its periphery engaging and releasablyrestraining the latch member, the trip bar being rotatably supported bythe supporting plates, a-trip member supported on the trip bar andassociated with the center 'pole unit, an insulating trip memberdisposed on each of'the outer ends of the trip bar, each of theinsulating trip members being associated 'With a dilferent one of thetwo outer pole units, the insulating trip members engaging the outersides of the two spaced supporting plates to prevent axial movement ofthe trip a of the two outer pole units, the insulating trip membersengaging the outer sides of the two spaced supporting plates to preventaxial movement of the trip bar, electromagnetic trip means in each ofthe three pole units comtrip bar to effect release of the latch memberto thereby release the operating mechanism.

8. A multi-pole circuit breaker having relatively movable contacts ineach pole unit, a single operating mechanism comprising a releasablemember pivotally supported I and having a latch part, said releasablemember being releasable to effect automaticopening of all of said contacts, a latch mechanism comprising a latch member engaging said latchpart to latch said releasable'member, a trip structure comprising acommon trip bar releasablv restraining said latch member; said trip barextendingtransversely in said circuit breaker on a first side of saidlatch part, a trip member for each pole unit and secured to the commontrip bar, electro-magnetic trip means in each pole unit positionedrelative to the length of said circuit breaker on a side of saidlatchpart that is opposite said first side, each of saidelectro-magnetic trip means comprising a magnetic member and .anarmaturedevice, upon'sufiicient the pole units the armature device in that poleunit moving to engage the trip member for that pole unit to move thetrip structure to effect release of the latch member to thereby effectrelease of the releasable member.

9. A multi-pole circuit breaker having relatively movv able contacts ineach pole unit, a single operating mechanism comprising a pivotallysupported releasable member releasable to effect automatic opening ofall of said contacts, said releasable member having a latch part, alatch mechanism comprising a latch member engaging saidlatch part tolatch said releasable member, a trip structure comprising a cylindricalcommon trip bar having its periphery 1 magnetic member, each of saidelectro-magnetic trip means comprising an armature pivotally supportedintermediate its ends, upon sutiicient energiZ-ation of theelectro-magnetic trip means in any of the pole units one end of theassociated armature being attracted to the associated magnetic member topivot the armature whereupon the other end thereof moves'to engage thetripmember in the asreleasable member.

References Cited in the file of this patent UNITED STATES PATENTSDorfman June 25, 1957 10 Dorfman et a1 Oct. 29', 1957 Christensen Feb.18, 1958 Ri'gert Nov. 1 1, 1958 Bodenschatz Apr. 12, 1960 MiddendorfJuly 5, 1960

1. A CIRCUIT BREAKER HAVING RELATIVELY MOVABLE CONTACTS AND MEANSRELEASABLE TO EFFECT OPENING OF SAID CONTACTS, A LATCH MECHANISMCOMPRISING A LATCH MEMBER ENGAGING AND RELEASABLY RESTRAINING THERELEASABLE MEANS, A TRIP STRUCTURE SEPARATE FROM THE LATCH MEMBER ANDLATCHING THE LATCH MEMBER IN LATCHING POSITION, ELECTROMAGNETIC TRIPMEANS COMPRISING A MAGNETIC MEMBER, AN ARMATURE STRUCTURE OPERABLE UPONSUFFICIENT ENERGIZATION OF THE ELECTROMAGNETIC TRIP MEANS TO ENGAGE ANDMOVE THE TRIP STRUC-